Mono-azo pigments



i r Y. I acid arylamide to form a compound ofthe general I MONO-AZOPIGMENTS Emil Stacker, Riehen, and Kurt E. Burdeska and Walter X X1 XStammhac'h, Basel, Switzerland, assignors to J. R. Geigy l I "A.G.,Basel, Switzerland 5 NH CO 01 No Drawing. Continuation-impart ofapplication S'er; No.

207,773, July '5,"'1962.' This application'May 10, 1965, 4 Ser.No.454,630 r Y e Claims priority, application Switzerland, July 6, 1961, 1

4 Claims. (Cl. 260-203) (II) 7 O CONHAI In the Formulas I and II, X X XX and X represent, independently of each other, hydrogen or chlorine; inA R OF THE CL SURE Forrliulllai II, Ar replrleslelnts abradigal of (tihebenzene or na t ene seriesw ic ma esu stitute -Azo pigments are providedhereln corresponding to the preferred class of azoypigments arecompounds of formula: the formula trichloropheuyl-NHC OQCI H X1 X1 I X5V v X3 NH-CO c1 X4 ILT=N I g, wherem trichlorophenyl 1s a memberselected from the OH ONHAr groupings I) I I C1 7 CI wherem X X X X and Xrepresent independently hydrogen I O1 and C1- or chlorine and of whichat least one and at most two being hydrogen and I 1 Ar represents anunsubstituted naphthyl, an unsubstiand is a member- Selectedfrom thegroup consisting tuted phenyl or a phenyl radical substituted by lowerof the following radicals alkyl, lower alkoxy or chlorine.

By the term lower as used herein, it is meant radicals CH3 CH3 I CH3 vwith at most 3 carbon atoms. The amines used according to the inventionas diazo r components are obtained by reacting, by known methods, CH3

40 3 nitro 4 chlorobenzoyl chloride or 3 nitro 4,6- dichlorobenzoylchloride, with the corresponding chloro- O OOCH anilines and thenreducing the nitro group to the amino group.

The following diazo components produce particularly n p y and p yvaluble azo pigments according to the invention:

4-chloro-3-aminobenzoic acid-2,3',4-trichloroanilide,.4-chloro-3-aminobenzoic acid-2,4',5-trichloroanilide,4-chloro-3-aminobenzoic acid-3',4',5-trichl0roanilide,4,6-'dichloro-3-aminobenzoic acid-2',4-dichloroanilide,4,6-dichloro-3-aminobenzoic acid-2',5,'-dichloroanilide,4,6-dichloro-3-aminobenzoic acid-2',3,4-trichloroanilide, and

4,6-dichloro-3-aminobenzoic acid-2',4',5-trichloroanilide.

, This is a continuation-in-part application of our copendingapplication Ser. No. 207,773, filed July 5, 1962. and now abandoned. A,v

The present invention concerns new azo pigments. In particular, itrelates to azo pigments which are fast to solvents, cross-lacquering,migration, light and heat. It has now been found that such az-opigments, are obmined a dialotiled amine t i n 4 5 arqmatically ,Some ofthe acid amides used as coupling components bbllfld chlorinqatoms ofthe'genemlform1a according to the invention obtained from 2 hydroxyr f vl naphthalene 3 carboxylic acid and an aromatic amine f, Y a havealready been described in the literature; they are produced in the knownmanner, for example, by reacting Q C 2 hydroxynaphthalene 3 carboxylicacid with the X I. liTHa p (I) desired aromatic amine in the presence ofphosphorus v a p trichloride as condensing agent. I is coupled with a 2hydroxynaphthalene 3 carboxylic Generally the coupling is performed inaqueous, ad-

vantageously, acid solution, possibly in the presence of water-miscible,inert, organic solvents, sometimes in the presence of low alcohols suchas methanol or ethanol, or in the presence of low ketones such asacetone.

The new azo pigments precipitate out from the reaction mixtureimmediately after the coupling. They can be isolated in the usual way.They can be used as crude products for many purposes but, if desired,they can be purified by an after-treatment. Thus, for example, theshade, the color-strength and covering power and the fastness tosolvents, migration, cross-lacquering, heat and light of the crudepigments can be improved by heating in inert organic solvents, e.g. inoptionally halogenated and/ or nitrated aromatic hydrocarbons or incertain organic nitrogen bases such as dimethyl aniline or pyridine.

Among the pigments according to the invention, particularly those whichfall under the formula trichlorophenyl-NH-COOCI OE C|ONH-Ar whereintrichlorophenyl represents the groupings and Ar represents one of thefollowing radicals:

CH3 CH3 naphthyl- 1) or naphthyl-(Z show especially in lacquers anunexpected improvement when conditioned with solvents which are wellknown to yield conditioned pigments of good fastness properties.Solvents tested were chlorobenzenes, especially o-dichlorobenzene,nitrobenzene, dimethylaniline and chloronaphthalene. While thestructurally closest known pigments conditioned with any of the abovesolvents show a marked decrease in color strength in stoving lacquers,the pigments according to the invention are practically free from lossin color strength.

The drawback of the known pigments becomes noticeable particularlystrongly when these pigments are used reduced with white pigment inautomotive enamels. Moreover, if necessary a softer texture of thepigments can be obtained by milling. They are milled either alone or inthe presence of milling additives, e.g. in the presence of inorganic ororganic salts which can later be removed with solvents and, optionally,in the presence of additional milling additives such as organicsolvents.

For this purpose, organic agents which are solid or liquid at roomtemperature can be used. For example the pigment dyestuffs isolated fromthe reaction mixture and dried are milled with dehydrated calciumchloride or with sodium sulphate or sodium chloride in the presence ofaliphatic or aromatic, optionally chlorinated, and/or nitratedhydrocarbons such as cyclohexane, benzene, toluene, naphthalene, mono-,dior tri-chlorobenzene, tetrachloroethane or nitrobenzene, low aliphaticketones such as, e.g. actone, or low aliphatic monoalcohols, e.g.methanol, ethanol or methoxyor ethoxy-ethanol. In some cases thepigments can also be refined by milling with or:

milling, the additives are removed; for example inorganic salts are,e.g. dissolved with Water and organic additives are optionally removedby extraction, by distillation or with steam.

The azo pigments according to the invention are suitable for variouspurposes: for example in printing inks for graphic purposes, in paintshaving an oily basis such as linseed oil paints, or those having anaqueous basis such as dispersion paints; in lacquers of various typessuch as, e.g. nitro or stoving lacquers. In addition they can be usedfor the coloring of viscose or cellulose acetate in the spinning mass,for the pigmenting of synthetic materials, such as polyethylene,polystyrene, polyvinyl chloride, the latter of which can also containplasticiscrs, of cellulose esters, of therm-osetting resins, or for thepigmenting of rubber, paper pulp or laminates, for the coating oftextiles and of synthetic leather, for pigment printing or for paddyeing of textiles.

The pigments according to the invention are particularly distinguishedby a very good fastness to cross-lacquering, light :and migration,resistance to solvents and pure shades.

Further details can be seen from the following ex- :amples. Where nototherwise expressly stated, parts are given as parts by weight. Thetemperatures are in degrees centigrade. The relationship of parts byweight to parts by volume is as that of grams to cubic centimeters.

EXAMPLE 1 3.5 parts of 4-chloro-3-aminobenzoicacid-2,3',4'-trichloroanilide (M.P. 205-206) in 100 parts ofconcentrated sulphuric acid are stirred at 18 with 5.1 parts by volumeof sulphuric acid/nitrosyl sulphuric acid mixture, corresponding to 1.27parts of HSO NO, for 1 hour. This mixture is then poured into 1000 partsof ice water and clarified by filtration. A solution of 2.75 parts of 2-hydroxynaphthalene-3-carboxylic acid anilide, in 120 parts of water and12.5 parts by volume of 2 N sodium hydroxide solution is then addeddropwise to the filtrate while stirring vigorously whereupon a redprecipitate is formed. The mixture is heated to 50 until no more diazocompound can be traced. The red azo dyestutf which has precipitated isfiltered, washed and dried at 60 A red pigment is obtained which isdistinguished by its beautiful shade, good fastness to cross-lacqueringin stoving lacquers, good migration fastness in polyvinyl chloride andits very good fastness to light. If desired, its colouristic propertiescan be still further refined by heating in toluene or dimethylaniline,filtering, washing with alcohol and drying. This red pigment can also beused for graphic or textile printing colours.

EXAMPLE 2 A diazo solution is produced according to Example 1 and, whilestirring well, the solution of 3.24 parts of2-hydroxynaphthalene-3-carboxylic acid-2-methyl-4' chloroanilide inparts of water and 25 parts by volume of 2 N sodium hydroxide solutionis added dropwise. The coupling is completed by heating to 50 and thedyestufi is filtered oif, washed, and dried at 60. A red pigment isobtained which is similar to that of Example 1. It has very goodfastness to solvents, cross-lacquering, migration, heat and light. I

On heating the pigment, for example, in nitrobenzene, dichlorobenzene ordimethyl aniline, filtering, washing with alcohol and drying, thefastness to cross-lacquering and migration can be further improved.

Similar valuable pigments are obtained on using equivalent amounts of2-hydroxynaphthalene-B-carbQXylic-acid- 2-methylanilide,-4-methylanilide, 3,4v-dimethylanilide, -2,4-dimethylanilide,-4'-ethylanilide, -2'-methoxyanilide, -4'-methoxyanilide, -2' methoxy 5'chloroanilide, -2'- ,5 methyl 4' methoxyanilide, -2' ethoxyanilide,-2',4'-dimethoxy-'-chloroanilide, -2,5'-dimethoxy-4'-chloroanilide,-2',4'-dichloroanilide, -1'-naphthylamide or -2'-naphthylamide ascoupling components in otherwise analogous procedure, using 50 parts byvolume of 2 N sodium hydroxide solution and 0.5 part of Turkey-red oil.

EXAMPLE 3 3.5 parts of 4-chloro-3-aminobenzoic acid-2',4',5'-tri'-chloroanilide (M.P. 190) in 50 parts of concentrated sulfuric acid arestirred for 1 hour at 18 with 5.1 parts by volume of sulfuricacid/nitrosyl sulfuric acid mixture corresponding to 1.27 parts of HSONO, whereupon this so1ution is poured into 1000 parts of ice water.

A solution, 60 warm, of 2.7 parts of 2-hydroxynaphthalene-3-carboxylicacid anilide in 180 parts of water and 25 parts by volume of 2 N sodiumhydroxide solution is added dropwise within minutes while stirring wellto this diazo mixture and the whole is heated to 50. On completion ofthe coupling, the reaction mixture is worked up as described in Example1 whereupon a red pigment having good fastness to cross-lacquering,migration and light is obtained. This pigment also can be refined byheating in organic solvents.

Valuable pigments are obtained if, instead of 2 119 EXAMPLE 4 3.5 partsof 4,6-dichloro-3-aminobenzoic acid 2,5'-dichloroanilide (M.P. 206") in50 parts of concentrated sulphuric acid are stirred at 18 with 5.1 partsby volume of a mixture of sulphuric acid and nitrosyl sulphuric acidwarm solution of 3.24 parts of 2-hydroxynaphthalene-3- carboxylicacid-2-methyl-4-chloroanilide in 120 parts of water and parts of 2 Nsodium hydroxide solution is added dropwise to the filtrate and thewhole is stirred at 50. On completion of the coupling, the reactionmixture is worked up as described in Example 1. A red pigment is soobtained which has very good fastness to cross-lacquering and light.

EXAMPLE 6 3.845 parts of 4,6-dichloro-3-aminobenzoic acid-2',4',-trichloroanilide (M.P. 256258) in 50 parts of concentrated sulphuricacid are stirred for 1 hour at 18 with 5.1 parts by volume of a mixtureof sulphuric acid and nitrosyl sulphuric acid, containing 1.27 parts ofHSO NO. The mixture is then poured into 2000 parts of ice water, thetemperature is raised to 15 and a 60 warm solution of 3.24 partsof2-hydroxynaphthalene-3-carboxylic acid- 2-methyl-4-chloroanilide in120 parts of water and 25 parts by volume of 2 N sodium hydroxidesolution is added dropwise while stirring well. The mixture is heated to5 -0-55 f until coupling is complete, it is then filtered and 2 Workedup as described in Example 1. In this way a red pigment is obtainedwhich has very good fastness to crosscontaining 1.27 parts of HSO NO.This mixture is then poured into 500 parts of ice water anda 60 warmsolu- 7 tion of 2.75 parts of 2-hydroxynaphthalene-3-carboxylic acidanilide in 120 parts of water and 12.5 partsby vol-' ume of 2 N sodiumhydroxide solution is added dropwise whereupon the whole is heated to50-55. On completion of the coupling, the reaction mixture is worked'upas described in Example 1. In this way a beautiful red pigment havinggood fastness to cross lacquering, migration and light is obtained.

A similar, good product is obtained by coupling 3.5 parts of4,6-dichloro-3-aminobenzoic acid-2,4'-dichloroanilide (M.P. 208-210)with 3.24 parts of 2-hydroxynaphthalene-3-carboxylic acid-2-methyl-4'chloroanilide using 25 parts by volume of sodium hydroxide solution.

EXAMPLE 5 lacquering, heat and light.

EXAMPLE 7 A stoving lacquer made from:

is finely milled in a ball mill, sprayed onto an aluminum sheet andfinally stoved for 30 minutes at C. The dyeing has very good fastness toheat and cross-lacquering and, in spite of the high dilution of thepigment, has excellent fastness to light.

EXAMPLE 8 A mixture consisting of:

' 67 parts of polyvinyl chloride,

33 parts of dioctyl phthalate,

2 parts of dibutyl tin dilaurate,

0.3 part of a sodium barium salt of an acid phosphoric acid alkyl ester,sold under the name of Ferroclere 541A by Pure Chemicals Limited,Liverpool, England, as light stabiliser,

2 parts of titanium dioxide, and

0.65 part of the pigment obtained from 4 chloro-3- aminobenzoic acid2,4',5 trichloroanilide and 2- hydroxy-naphthalene 3 carboxylic acid 2'naphthylamide, which pigment has been heated in dimethyl aniline,filtered, washed with methanol and dried, is worked up on a set ofmixing rollers at C. and then drawn out into a film of 0.4 mm.thickness. The dyeing has good fastness to migration, light and heat.

We claim: 1. The compound of the formula I N=N H3 1 I H0 (JO-NHO-OCHaCPQ-NH-C oQm 3. The compound of the formula OH (BO-NH- 4. The compoundof the formula v Cl CPQNH l N N E:

| H?) o-NHOocHa References Cited UNITED STATES PATENTS 2,703,319 3/1955Fischer 260-203 FOREIGN PATENTS 889,739 9/1953 Germany.

CHARLES B. PARKER, Primary Examiner.

D. M. PAPUGA, Assistant Examiner.

